方法一：设置barbuttonitem的文本样式为透明颜色，代码如下：
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[[uibarbuttonitem appearance] settitletextattributes:@{nsforegroundcolorattributename: [uicolor clearcolor]} forstate:uicontrolstatenormal];
[[uibarbuttonitem appearance] settitletextattributes:@{nsforegroundcolorattributename: [uicolor clearcolor]} forstate:uicontrolstatehighlighted];
此外这种方法会导致title不能居中，被偏移很多，如下所示（虽然不被显示，也占了导航栏左边很大一部分位置）
方法二：给uiviewcontroller添加类别，然后在load方法里面用method swzilling方法替换 交换viewdidappear，部分代码如下
+(void)load {
swizzlemethod([self class], @selector(viewdidappear:), @selector(ac_viewdidappear));
}
- (void)ac_viewdidappear{
self.navigationitem.backbarbuttonitem = [[uibarbuttonitem alloc]
initwithtitle:@""
style:uibarbuttonitemstyleplain
target:self
action:nil];
[self ac_viewdidappear];
}
void swizzlemethod(class class, sel originalselector, sel swizzledselector)
{
// the method might not exist in the class, but in its superclass
method originalmethod = class_getinstancemethod(class, originalselector);
method swizzledmethod = class_getinstancemethod(class, swizzledselector);
// class_addmethod will fail if original method already exists
bool didaddmethod = class_addmethod(class, originalselector, method_getimplementation(swizzledmethod), method_gettypeencoding(swizzledmethod));
// the method doesn't exist and we just added one
if (didaddmethod) {
class_replacemethod(class, swizzledselector, method_getimplementation(originalmethod), method_gettypeencoding(originalmethod));
}
else {
method_exchangeimplementations(originalmethod, swizzledmethod);
}
}
注意事项：
要给整个backbuttonitem赋值才可以，👇这种方法不行，因为backbarbuttonitem默认为空，给nil方法消息，默认声明都不执行（）
self.navigationitem.backbarbuttonitem.title = @" ";
leftbarbuttonitem 与backbarbuttonitem 的显示关系：
有leftbarbuttonitem则优先显示当前vc的leftbarbuttonitem，无则显示上个vc的backbarbuttonitem，再无则显示上个vc的title（ 还是官网解释的清楚）
总结
以上所述是小编给大家介绍的ios 11 使用两种方法替换(method swizzling)去掉导航栏返回按钮的文字，希望对大家有所帮助
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